Explosive reactive armor for the protection of personnel residing inside a protected structure against impinging projectiles is well known to the art.
Explosive reactive armor consists of a layered explosive sandwiched between two steel plates and packages as a cassette. Armored vehicles, such as tanks, are appropriately covered, on the outside, with contiguously mounted explosive reactive armor cassettes as a measure of protection from the enemy. When a projectile impinges, preferably obliquely on the explosive reactive armor, an explosion is initiated, and a reaction occurs. The term projectile defines any kind of armor penetrating weapon, such as a kinetic energy projectile, or a hollow charge, or a shaped charge, or a high velocity slug.
FIG. 1 shows a diagrammatic cross-section of an explosive reactive armor cassette, with a front plate FP, a back plate BP, and an intermediate plate IP, or plate of explosive EX, or fast exothermic reaction composition EX. The direction of the impinging projectile is indicated by the arrow marked VP. The front plate FP faces the front F directed towards the incoming projectile and the back B indicates the opposite direction adjacent the structure protected by the explosive reactive armor.
As a result of the explosive reaction, the two steel plates, FP and BP, are accelerated in separation, in opposite directions, normal to their surface. FIG. 2 shows the direction of acceleration for both the front plate FP and the back plate BP by arrows designated as respectively VFP and VBP. The translation of both plates actively interacts with the motion of the projectile, not shown in the FIGS., by crossing the trajectory thereof and hitting the projectile. Thereby, the projectile is broken and the severe perturbations that are caused, lead to a drastic reduction of the subsequent penetration capability of that projectile.
Details about the physical mechanism of projectile dispersion and deflection resulting from the operation of the explosive reactive armor are found in the reference paper entitled “Interaction of Shaped-Charge Jets with Reactive Armor”, by M. Mayseless et al., Proceedings of the Eight International Symposium on Ballistics, Orlando, Fla., USA, Oct. 23-25, 1984, which is incorporated herewith in whole by reference.
Although the two steel plates of an explosive reactive armor begin their protective effect as single-piece solid plates stacked in surface abutment as a cassette mounted outside the protected structure, they shatter into fragments a few microseconds after the initiation of the explosive reaction. From this moment on, the fragments of the plates of the reactive armor develop into a life-threatening danger, scattering as shrapnel on the outside of the protected structure. Fragments from the front plate FP endanger personnel, equipment, and vehicles dwelling on the outside of the protected structure, while fragments from the back plate BP, badly damage the protected structure itself. Even though the main objective of the explosive reactive armor is achieved and the personnel inside the protected structure escapes unharmed, by-standing troops may be killed or seriously wounded, and equipment may be destroyed by fragments from the front plate FP. In addition, the back plate BP, usually abutting and contiguous to, for example, the armor of an armored vehicle, may inflict so much damage as to render it unfit for service.
Furthermore, the contiguously mounted steel plates of the explosive reactive armor cassettes support sympathetic initiation, whereby the explosive reaction of one explosive reactive armor cassette triggers the reaction of neighboring cassettes, causing an unnecessary reaction, and thus waste, of a number of such protection cassettes.
It is thus desirable to provide a solution to prevent or mitigate the harm caused on the outside of the protected structures to nearby troops and to equipment, when an explosive reactive armor scatters fragments. This solution is also necessary to prevent damage to the protected structure itself, but the beneficial protective effect of the explosive reactive armor must be retained.
Moreover, sympathetic reaction is detrimental to the degree of protection of the protected structure and requires repair time for replacement of the spent protection cassettes. Therefore, sympathetic reaction is preferably prevented.
Prior art solutions for the protection from harm inflicted by the fragments resulting from the explosion of an explosive reactive armor are not known to have been disclosed.